The production of a spheroidally, or more particularly a spherically, contoured fabric of material which is difficult to weave, such as a carbon fiber material, has become desirable in recent times for use in the formation of shims for spherically shaped rocket nozzle parts, for use in the construction of parabolic antennae, and as bases or cores for radar domes made of resin or the like.
In the conventionally finished product, while the warp yarns or threads will be substantially circumferential around the axis of a sphere, in the nature of the latitude lines on a globe, the weft yarns or threads will not run in planes parallel to the axis of the sphere, in the nature of longitude lines on a globe, but rather will be caused to curve away from such positions from the larger diameter edge of the spherical portion to the smaller diameter edge. This problem will be discussed more fully hereinafter. This distortion of the position of the weft yarns or threads makes the fabric unsatisfactory.
Another property of spheroidally contoured fabric is that if it is shaped from fabric in which the weft yarns and warp yarns are uniformly spaced across the fabric, when the fabric is shaped into a spherical shape, the weft yarns will be closer together at the portion of the fabric nearer the pole of the sphere, i.e. the fibers lying along longitude lines of the sphere will converge toward the poles, so that the density of the fabric will increase toward the poles of the spheroid. This can be undesirable.